Zentrierung der Titelseite im Tuftebook

Question

Ich versuche, im Unterricht ein Titelblatt zu erstellen tufte-book. Das ist, was ich will, wenn ich PDFLaTexfür den Schriftsatz verwende:

Aber wenn ich xepersianein Paket verwende, muss ich es xelatexfür den Schriftsatz verwenden, was zu folgendem Ergebnis führt:

Ich kann nicht herausfinden, warum das passiert??

\documentclass[11pt,fleqn]{tufte-book} % Default font size and left-justified equations

\usepackage{tikz} 
\usetikzlibrary{calc}
\usetikzlibrary{backgrounds}
\usepackage{epigraph}
\newlength{\drop}
\renewcommand\epigraphflush{flushright}
\renewcommand\epigraphsize{\normalsize}
\setlength\epigraphwidth{0.7\textwidth}

\definecolor{titlepagecolor}{rgb}{0,1,0}

\DeclareFixedFont{\titlefont}{T1}{ppl}{b}{it}{0.5in}

\newcommand\KNTU{%

\begin{tikzpicture}[scale=.5]
  \def\Unit{30pt}
  \def\InnerLineWidth{4pt}
  \def\OuterLineWidth{1pt}
  \definecolor{OuterLineColor}{rgb}{.15, .15, .55}
  \definecolor{InnerLineColor}{rgb}{.55, .85, .97}
  \def\LineDrawing{%
    (0,0) coordinate (A)
    \foreach \p/\a in {
      B/-30, C/30, D/-30, E/30,
      F/90, G/150, H/90, I/150,
      J/210, K/-90, L/210%
    } {
      -- ++(\a:\Unit) coordinate (\p)
    } -- cycle
    (A)
    \foreach \p in {A, B, C, D, E} {
      -- ($(\p) + (-90:\Unit)$) coordinate (\p2)
    }
    -- (E)
    \foreach \p in {E, F, G, H, I} {
      -- ($(\p) + (30:\Unit)$) coordinate (\p2)
    }
    -- (I)
    \foreach \p in {I, J, K, L, A} {
      -- ($(\p) + (150:\Unit)$) coordinate (\p2)
    }
    -- cycle
    \foreach \p in {
      B, C, D,
      F, G, H,
      J, K, L%
    } {
      (\p) -- (\p2)
    }
  }
  \begin{scope}
  \fill[black, line width=\InnerLineWidth + 2 * \OuterLineWidth]
    \LineDrawing
  ;
  \fill[black, line width=\InnerLineWidth]
    \LineDrawing
  ;
  \end{scope}
\end{tikzpicture}%
}


%
%\usepackage{xepersian}
%\settextfont{XB Zar}

\begin{document}

%----------------------------------------------------------------------------------------
%   TITLE PAGE
%----------------------------------------------------------------------------------------

\thispagestyle{empty}
\begin{titlepage}
\begin{fullwidth}

\centering
\KNTU
\\
\noindent
\textcolor{black}{{
سسسسسسسسسسس\\
دانسسسسسسسسی\\
something\\
}}

\drop=0.1\textheight
    \centering
    \vspace*{\baselineskip}
    \rule{\textwidth}{1.6pt}\vspace*{-\baselineskip}\vspace*{2pt}
    \rule{\textwidth}{0.4pt}\\[\baselineskip]
    {\large
     گزسسسسسسسسسسسسسسس\\
     }

    \rule{\textwidth}{0.4pt}\vspace*{-\baselineskip}\vspace{3.2pt}
    \rule{\textwidth}{1.6pt}\\[\baselineskip]

    \vspace*{3\baselineskip}
    نگارش: \\[\baselineskip]
    {\large


    something}
    \vspace*{3\baselineskip}

    استاد: \\[\baselineskip]
    {\large

     دکتر }
    \vspace*{3\baselineskip}
    \vfill

    {\large 1395-96}\par

\end{fullwidth}
\end{titlepage}

\end{document}